Process for disposing of spent NaS cells

ABSTRACT

A process is disclosed for disposing of a spent NaS cell, which process comprises the steps of: cutting an opening in the NaS cell for flowing out sodium from the cell and allowing an inner tube to be pulled out from the NaS cell; placing oil on sodium inside the inner tube of the spent NaS cell in a given thickness, while the cut opening is directed upwardly; setting the spent NaS cell in a workpiece-setting vessel outside a heating oil vessel, while the cut opening is directed downwardly, thereby flowing out the oil on the sodium inside the inner tube, said workpiece-setting vessel being provided at a bottom with a hole for allowing an inner tube to be pulled out from the the spent NaS cell, immersing the spent NaS cell set in the workpiece-setting vessel into oil in the heating oil vessel in the state that the cut opening is directed downwardly; sodium is melted in the oil of the heating oil vessel and flown out therein through the cut opening; and then the inner tube is pulled out from the NaS cell.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a process and an apparatus fordisposing of spent NaS cells.

(2) Related Art Statement

The NaS cell is a cell in which sodium and sulfur are placed in oppositesides of an intermediate tube made of a solid electrolyte, respectively.Such NaS cells have been developed as cells for storing a large amountof electric power and as cells for use in electric automobiles. However,since the service life of the NaS cell is considered to be about 10years, it is anticipated that a huge number of spent NaS cells will comeout in the future.

The present inventors have been developing techniques for disposing ofspent NaS cells herald of the world. Inventors' past research revealedthat in order to recover sodium and sulfur from the interior of the NaScell, an opening needs to be formed in the NaS cell that has acomplicated multi-tubular structure by cutting to recover the sodium.Then, an inner tube needs to be removed from the NaS cell. During theresearch, it has been revealed that although sodium can flow from theinterior of the NaS cell inside an oil vessel in a state such that thecut opening is directed downwardly, the inner tube needs to be pulledout from the NaS cell inside a heating oil vessel filled with a flowingparaffin or the like so as to prevent the sodium from contacting air.Further, it was revealed that when the above opening is cut and formedin the NaS cell inside oil, oxidization of sodium can be effectivelyprevented. However, even when the inner tube is pulled out after thespent NaS cell having the opening cut is immersed in the oil inside theheating oil vessel in the state that the cut opening is directeddownwardly and then sodium is melted and to flow out and into the oil,various problems exist. That is, if the NaS cell is left for a longtime, after the formation of the cut opening, in the state that theopening is directed downwardly, sodium inside the inner tube contactsair so that an oxide film is formed at the surface of sodium.Consequently, even if the NaS cell is heated in the heating oil vesseland it is melted, it is difficult for the sodium to flow due to theexistence of the oxide film, and it takes a long time to discharge thesodium. It was further revealed that in order to smoothly extract thesodium, it is necessary to remove the oxidization film.

SUMMARY OF THE INVENTION

It is an object of the present invention to solve the above-mentionedconventional problems, and to provide a process and an apparatus fordisposing of spent NaS cells, which process and apparatus caneffectively prevent oxidation of sodium, and smoothly extract sodiuminside oil in a heating oil vessel so that the inner tube of the spentNaS cell may be smoothly pulled out from the spent NaS cell.

According to the process for disposing of the spent NaS cells in a firstaspect of the present invention, the process comprises the steps of:cutting an opening in the NaS cell for flow of the sodium and allowingan inner tube to be pulled out from the NaS cell; placing oil on sodiuminside the inner tube of the spent NaS cell in a given thickness, whilethe cut opening is directed upwardly; setting the spent NaS cell in aworkpiece-setting vessel outside a heating oil vessel, while the cutopening is directed downwardly, such that the oil on the sodium insidethe inner tube flow out, said workpiece-setting vessel being provided ata bottom with a hole for allowing an inner tube to be pulled out fromthe spent NaS cell; immersing the spent NaS cell set in theworkpiece-setting vessel into oil of a heating oil vessel in the statethat the cut opening is directed downwardly; sodium is melted in the oilinside the heating oil vessel and flows out through the cut opening; andthen the inner tube is pulled out from the NaS cell.

The following are preferred aspects of the spent NaS cell disposalprocess.

(1) Said cut opening includes a first opening for allowing the innertube from the spent NaS cell and a second opening for flow of thesodium, the first opening is formed at the spent NaS cell by cutting,and then the second opening is formed at the NaS cell.

(2) The opening of the spent NaS cell is cut in oil of anopening-cutting oil vessel to place oil on sodium inside the inner tubein a given thickness through the cut opening; a lower portion of thespent NaS cell in which the oil is placed on the sodium inside the innertube is set inside a pressing vessel member arranged outside theopening-cutting oil vessel and the heating oil vessel in the state thatcut opening is directed upwardly; said workpiece-setting vessel beingprovided at the bottom with the hole for allowing the inner tube to bepulled out from the the spent NaS cell is arranged onto the pressingvessel member, thereby accommodating the spent NaS cell between andinside the pressing vessel member and the workpiece-setting vessel; thepressing vessel member, the workpiece-setting vessel and the spent NaScell are vertically inversed to downwardly direct the cut opening of thecell between the pressing vessel member and the workpiece-setting vesseland permit flow of the oil from inside the inner tube; and the spent NaScell set between the pressing vessel member and the workpiece-settingvessel is immersed into the oil inside the heating oil vessel.

(3) The pressing vessel member, the workpiece-setting vessel and thespent NaS cell are vertically inversed to downwardly direct the cutopening of the NaS cell between the pressing vessel member and theworkpiece-setting vessel and to permit flow of the oil from inside theinner tube; the pressing vessel member is removed; and the spent NaScell set in the workpiece-setting vessel is immersed into the oil insidethe heating oil vessel in the state that the cut opening is directeddownwardly.

(4) Immediately before the spent NaS cell is immersed into the oil ofthe heating oil vessel, the pressing vessel member, theworkpiece-setting vessel and the spent NaS cell are vertically inversedto downwardly direct the cut opening of the NaS cell between thepressing vessel member and the workpiece-setting vessel and to permitflow of the oil from inside the inner tube; and the spent NaS cell isset between the pressing vessel member and the workpiece-setting vesselis immersed into the oil inside the heating oil vessel in the state thatthe cut opening is directed downwardly.

(5) The opening is formed by cutting the spent NaS cell inside the oilin the opening-cutting oil vessel, and the oil is placed on the sodiuminside the inner tube inside the opening-cutting oil vessel in a giventhickness.

The spent NaS cell disposal apparatus according to the present inventioncomprises:

1 a workpiece-setting vessel having a hole at a bottom portion forallowing an inner tube of a spent NaS cell to be pulled out from the NaScell, said workpiece-setting vessel adapted to hold and support thespent NaS cell in the state that a cut opening of the NaS cell forflowing of sodium therefrom and pulling out an inner tube from the spentcell is opposed to the hole of the NaS cell;

2 an heating oil vessel into which the spent NaS cell is immersed,sodium inside the inner tube of the cell flows through the cut openingof the NaS cell, and the inner tube is pulled out from the spent NaScell;

3 a transporting elevator adapted to reciprocate along a reciprocatingbeam extending above the heating oil vessel and between above theheating oil vessel and outside the heating oil vessel, said transportingelevator being adapted to hold the workpiece-setting vessel at a lowerend portion, to be descended from the location above the heating oilvessel and to immerse the NaS cell held by the workpiece-setting vesselinto oil inside the heating oil vessel for flow of the sodium therefromand to take the spent NaS cell out from the heating oil vessel after theinner tube is taken out from the NaS cell; and

4 an extractor for extracting the inner tube of the spent NaS cell afterthe sodium flow from the NaS cell inside the oil in the heating oilvessel in the state that the cut opening is directed downwardly.

The following are preferred embodiments of the spent NaS cell disposalapparatus according to the present invention.

(1) The spent NaS cell disposal apparatus further comprises a cutter forforming a first opening at the spent NaS cell by cutting, said firstopening being adapted to pull out the inner tube from the spent NaScell, an opening-cutting oil vessel in which the spent NaS cell isimmersed in oil and a second opening is formed in the NaS cell bycutting, and a cutter for cutting said second opening in the spent NaScell in the oil in the opening-cutting oil vessel, said second openingbeing adapted for flow of the sodium from the cell and to place the oilon the sodium in the spent NaS cell through the first and secondopenings.

(2) The spent NaS cell disposal apparatus further comprises a pressingvessel member which is to be detachably attached to theworkpiece-setting vessel, said pressing vessel member being adapted tohold the spent NaS cell between the workpiece-setting vessel and toenable the cell to be vertically inversed in the state that the spentNaS cell is held between the pressing vessel member and theworkpiece-setting vessel.

(3) A rail for supporting the workpiece-setting vessel in which thespent NaS cell is held while the cut opening is directed downwardly, isprovided in the heating oil vessel, a location for flow of the sodiumfrom the NaS cell is provided in the heating oil vessel separately froma location for pulling out the inner tube from the spent NaS cell, saidrail is extended between the sodium flow location (outlet) and the innertube pull-out location, and a first carrier is provided to move thespent NaS cell along the rail from the sodium flow location to the innertube pull-out location.

(4) The spent NaS cell disposal apparatus further comprises a secondcarrier for moving the pressing vessel member removed from theworkpiece-setting vessel, after the vertical inversion, to a location toreceive a next spent NaS cell in which the cut opening is formed and oilis placed on sodium inside the inner tube in the state that the cutopening is directed upwardly, and a third carrier for moving theworkpiece-setting vessel to a location where the workpiece-settingvessel receives the next spent NaS cell.

(5) The above transporting elevator comprises first through thirdtransporting elevators, said first transporting elevator being adaptedto reciprocate along the reciprocating beam extending above the heatingoil vessel and between above the heating oil vessel and outside theheating oil vessel, and being adapted to hold the workpiece-settingvessel at a lower end portion, to be descended from the location abovethe heating oil vessel, and to immerse the NaS cell held by theworkpiece-setting vessel into oil in the heating oil vessel for flow ofthe sodium therefrom, said second transporting elevator being adapted tomove the spent NaS cell to the inner tube pull-out location after thesodium is melted and removed from the spent NaS cell, and said thirdtransporting elevator for taking out the remaining spent NaS cell outfrom the heating oil vessel after the inner tube is pulled outtherefrom.

The spent NaS cell generally has a structure as shown in Japanese patentapplication Laid-open No. 3-88281 by way of example. That is, inside anouter tube are arranged a carbon mat tube (anode), a solid electrolytetube (β-alumina tube), a safety tube and an inner tube in this orderfrom radially inner to outer sides, and an open end of the solidelectrolyte tube is sealed with a cathode cap (See FIG. 12). In such anNaS cell, the cathode cap is formed with an opening for allowing theinner tube to be pulled out from the cell, by appropriate cutting means.Then, an opening for flow of the sodium from the cell is formed in asealed end portion of the inner tube exposed through the opening of thecathode cap. In order to facilitate the pull-out of the inner tube fromthe cell through the inner tube pull-out opening, it is preferable thatthe diameter of the sodium flow-out opening is substantially equal to orslightly smaller than the inner diameter of the inner tube.

According to the spent NaS cell disposal process according to thepresent invention, after the sodium discharge opening is bored in thespent NaS cell, the surface of sodium inside the inner tube is coveredwith oil inside the heating oil vessel in the state that the cut openingis directed downwardly, until the cell is immersed into the oil in theheating oil vessel. Therefore, the formation of an oxidized film at thesurface of the sodium can be prevented. Although the oil is dischargedfrom the spent NaS cell by vertically inverting the spent NaS cell sothat the cut opening may be directed downwardly, the cell is immersedinto the oil in the heating oil vessel before the oil film at thesurface of the sodium is broken. Consequently, the formation of theoxidized film at the surface of the sodium can be prevented. Further,since the NaS cell is immersed into the heating oil vessel in the statethat the cut opening is directed downwardly, air is taken into a spaceunder the sodium inside the inner tube of the cell. Consequently, theair taken into the space is heated and thermally expanded, so that themelted sodium is discharged from the cell in a shorter time.

Further, according to the preferred embodiment of the process of thepresent invention, since the opening is formed at the upper portion ofthe spent NaS cell by cutting in the oil inside the oil vessel, oilimmediately enters the space over the sodium inside the inner tube.Consequently, the oxidation of the surface of the sodium can be moreeffectively prevented, so that the sodium can smoothly flow out and beremoved.

The spent NaS cell disposal apparatus of the present invention comprisesthe workpiece-setting vessel, the heating oil vessel, the transportingelevator and the extractor recited in the above 1- 4, respectively.Therefore, it is possible to continuously and smoothly discharge thesodium from the spent NaS cell having the cut opening and pull out theinner tube from the outer tube of the cell.

On the other hand, the preferred embodiment (1) of the NaS cell disposalapparatus of the present invention comprises the opening-cutting oilvessel in which the spent NaS cell is immersed and the opening is formedin oil by cutting, and the cutter for cutting the opening in the spentNaS cell inside oil of the opening-cutting oil vessel to enter the spaceover the sodium inside the inner tube. Thus, since the opening is cutand opened at the upper portion of the spent NaS cell inside the oil ofthe opening-cutting oil vessel, the oil immediately enters the spaceover the sodium inside the inner tube through said cut opening. Theoxidation of the surface of sodium can be more effectively prevented,and the sodium can smoothly flow out and be removed.

The preferred embodiment (2) of the spent NaS cell disposal apparatus ofthe present invention further comprises the pressing vessel member whichis to be detachably attached to the workpiece-setting vessel, so as tohold the spent NaS cell between the workpiece-setting vessel and enablethe cell to be vertically inverted. The pressing vessel member isdetachably attached to the workpiece-setting vessel, and can be detachedfrom the workpiece-setting vessel. Therefore, the spent NaS cell heldbetween the pressing vessel member and the workpiece-setting vessel isimmersed into the oil of the heating oil vessel, the pressing vesselmember can be taken out from the oil vessel, while the workpiece-settingvessel with the spent NaS cell is left in the oil for disposing of thecell. Alternatively, only the workpiece-setting vessel into which thespent NaS cell is placed is immersed in the oil of the heating oilvessel after the pressing vessel member is detached from theworkpiece-setting vessel. Consequently, the structure of the disposalapparatus is simplified. In this embodiment, once the spent NaS cell isinserted into the pressing vessel member in the state that the cutopening is directed upwardly and oil is placed on the sodium inside theinner tube, it is possible that the workpiece-setting vessel is placedto cover the pressing vessel member and the spent NaS cell, the assemblyof the pressing vessel member, the workpiece-setting vessel and thespent NaS cell are vertically inverted outside the heating oil vesselfor flow of the oil on the sodium inside the inner tube, and the cell inthe workpiece-setting vessel is immersed into the oil of the heating oilvessel. Therefore, the spent NaS cell can be stored without causingoxidation of sodium in the state that oil is placed on the sodium insidethe inner tube of the cell, while the cut opening is directed upwardly.Further, the spent NaS cell in the state that the cut opening isdirected upwardly can be vertically inverted, while being assuredlyheld.

The preferred embodiment (3) of the spent NaS cell disposal apparatusaccording to the present invention comprises a rail for supporting theworkpiece-setting vessel in which the NaS cell is held while the cutopening is directed downwardly, is provided in the heating oil vessel,the location for flowing down the sodium is provided apart from thelocation for pulling out the inner tube from the NaS cell, said rail isextended between the sodium flow location and the inner tube pull-outlocation, and the first carrier is provided to move the spent NaS cellalong the rail from the sodium flow location to the inner tube pull-outlocation. Therefore, the spent NaS cells can be simultaneously treatedin the sodium flow location and the inner tube pull-out location. Thus,the spent NaS cells can be more efficiently disposed.

The above preferred embodiment (4) of the spent NaS cell disposalapparatus according to the present invention further comprises thesecond carrier for moving the pressing vessel member removed from theworkpiece-setting vessel, after the vertical inversion, to a location toreceive the spent NaS cell in which the cut opening is formed and oil isplaced on sodium inside the inner tube in the state that the cut openingis directed upwardly, and the third carrier for moving theworkpiece-setting vessel, after removing the remaining portion of theNaS cell from the workpiece-setting vessel, to a location where theworkpiece-setting vessel receives the next spent NaS cell. Therefore,the spent NaS cells can be continuously disposed of in a circulatoryfashion.

According to the preferred embodiment (5) of the spent NaS cell disposalapparatus of the present invention, the above transporting elevatorcomprises the first through third transporting elevators, said firsttransporting elevator being adapted to reciprocate along thereciprocating beam extending above the heating oil vessel and betweenabove the heating oil vessel and outside the heating oil vessel, andadapted to hold the workpiece-setting vessel at a lower end portion, tobe descended from the location above the heating oil vessel and toimmerse the NaS cell held by the workpiece-setting vessel into oil ofthe heating oil vessel for flow of the sodium, the second transportingelevator being adapted to move the NaS cell to the inner tube pull-outposition after the sodium is melted and removed, and the thirdtransporting elevator for taking out the spent NaS cell out from theheating oil vessel after the inner tube is pulled out. Therefore, thespent NaS cells can be smoothly and continuously disposed of along agiven line.

In the above, the process and the apparatus for disposing of the spentNaS cell according to the present invention has been described withrespect to a single spent NaS cell. However, a plurality of the spentNaS cells can be disposed of in a lump according to present invention asmentioned later.

These and other objects, features and advantages of the invention willbe appreciated upon reading of the following description of theinvention when taken in conjunction with the attached drawings, with theunderstanding that some modifications, variations and changes of thesame could be easily made by the skilled person in the art to which theinvention pertains.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention reference is made to theattached drawings, wherein

FIG. 1 is a schematic view for illustrating an embodiment of the processand the apparatus for disposing of the spent NaS cell according to thepresent invention;

FIG. 2 is a schematic view for illustrating another embodiment of theprocess and the apparatus for disposing of the spent NaS cell accordingto the present invention;

FIG. 3 is a schematic view for illustrating a further embodiment of theprocess and the apparatus for disposing of the spent NaS cell accordingto the present invention;

FIG. 4 is a schematic view for illustrating an opening-cutting oilvessel and a cutter used in the process and the apparatus for disposingof the spent NaS cell according to the present invention;

FIGS. 5(a) and (b) are schematic views for illustrating aworkpiece-setting vessel and a pressing vessel member to be used for theprocess and the apparatus for disposing of the spent NaS cell accordingto the present invention;

FIG. 6 is a schematic view for illustrating a part of the embodiment ofFIG. 1 for the process and the apparatus for disposing of the spent NaScell according to the present invention in more detail;

FIG. 7 is a schematic view for illustrating a holding head to be used inthe embodiment of FIGS. 1 and 6 for the process and the apparatus fordisposing of the spent NaS cell according to the present invention;

FIG. 8 is a schematic view for illustrating a sector gear of the holdinghead;

FIG. 9 is a schematic view for illustrating a state in which the holdinghead having the spent NaS cells are fixedly held between theworkpiece-setting vessel and the holding member is immersed into anheating oil vessel;

FIG. 10 is a view for illustrating a state in which theworkpiece-setting vessel with the spent NaS cells is placed on rails andthe chucking state of the holding head is released;

FIGS. 11(a) and 11(b) are views for illustrating a chuckingpawl-operating mechanism; and

FIG. 12 is a sectional view for illustrating the structure of an NaScell by way of example.

DETAILED DESCRIPTION OF THE INVENTION

In the following, the process for disposing of the spent NaS cellsaccording to the present invention will be explained in more detail.

The NaS cell generally is closed at one end with the other sealed, andsodium and sulfur are sealed in opposite sides of a partition made of anelectrolyte, respectively. According to the invention process fordisposing of the spent NaS cell, an opening for flowing the sodium fromthe spent NaS cell and allowing an inner tube to be pulled out from thecell is formed in the spent NaS cell by cutting, and a given amount ofoil is poured onto sodium inside an inner tube through the cut openingdirected upwardly. At that time, the above cut opening is preferablyconstituted by a first opening for allowing the inner tube from the celland a second opening for flow of the sodium from the cell. In this case,the first opening is formed in the cathode cap by cutting, and thesecond opening for flowing out the sodium from the spent NaS cell isformed by cutting inside oil of an opening-cutting oil vessel to flowoil onto the sodium inside the inner tube in a given thickness. By sodoing, sodium is prevented from contacting air, so that the formation ofan oxidized film at the surface of sodium can be prevented. Thereafter,the spent NaS cell is set in a workpiece-setting vessel having a holefor allowing the inner tube to be pulled out from the cell, in the statethat the above cut opening of the cell is directed downwardly for flowof the oil from the cell. Alternatively, it may be that once the cell isset inside a pressing vessel member in the state that the cut opening isdirected upwardly, the workpiece-setting vessel having the hole forpulling out the inner tube is arranged to cover the pressing vesselmember and to hold the spent NaS cell therebetween, and then thepressing vessel member, the workpiece-setting vessel and the spent NaScell are vertically inverted to hold the cell inside theworkpiece-setting vessel in the state that the cut opening is directeddownwardly for flow of the oil on the sodium inside the inner tube. Atthat time, before the assembly of the workpiece-setting vessel, thepressing vessel member and the spent NaS cell is immersed, the pressingvessel member placed upwardly by inverting may be removed. After the oilflows out through the downwardly directed cut opening of the cell, thespent NaS cell set in the workpiece-setting vessel is immersed intoheated oil, such as flowing paraffin, filled in a heating oil vessel,while the cut opening is kept directed downwardly. Then, the sodiuminside the cell is melted and flows down in the oil of the heating oilvessel through the downwardly directed cut opening of the cell and theinner tube-removing hole of the workpiece-setting vessel. Thereafter,the inner tube is pulled out from an outer tube of the spent NaS cell inthe oil of the oil heating vessel. The remaining cell is then pulled outfrom the oil of the heating oil vessel.

In the above, the disposal of a single spent NaS cell per one process isexplained. It may be that a plurality of holes for pulling out the innertubes of the cells are provided in the workpiece-setting vessel, and aplurality of the spent NaS cells are disposed of together.

Next, the spent NaS cell disposal process and the apparatus foreffecting the above disposal process according to the present inventionwill be explained by using schematic views illustrated in FIGS. 1through 3.

In a first embodiment of FIG. 1, an opening is formed in a spent NaScell by cutting, so that oil is poured onto sodium inside an inner tube[See FIG. 1(1)]. As an opener, an opener illustrated in FIG. 4 may beused, which will be explained later. In this case, the first opening forallowing the inner tube to be pulled out from the cell is formed in thecathode cap by a cutter not shown, and then the second opening for flowof the sodium from the cell is formed by the opener. Next, a pluralityof such spent NaS cells are manually or automatically inserted intorespective locations of a pressing vessel member placed on a conveyorsuch that the cut openings of the spent NaS cells are directed upwardly[See FIG. 1(2)]. Then, the pressing vessel member into which the pluralspent NaS cells are inserted is moved onto a succeeding conveyor, and aworkpiece-setting vessel having holes for pulling out inner tubes fromthe spent NaS cells, respectively, is placed to cover the pressingvessel member. Thereby, the spent NaS cells are fixedly held between thepressing vessel member and the workpiece-setting vessel in the statethat the cut openings of the cells face the respective inner tubepull-out holes of the workpiece-setting vessel [FIG. 1(3)]. Next, thepressing vessel member and the workpiece-setting vessel are verticallyinverted together with the spent NaS cells by using an inverter providedat a transporting elevator not shown, so that the cells are held insidethe workpiece-setting vessel and the pressing vessel member in the statethat cut openings are directed downwardly. Thereby, the oil inside thecells flows out [FIG. 1(4)]. On the other hand, the spent NaS cells heldbetween the workpiece-setting vessel are immersed into oil in a heatingoil vessel by means of the transporting elevator, and theworkpiece-setting vessel is placed on rails [See FIG. 1(6)]. Thepressing vessel member located upwardly by the above inversing is takenout from the heating oil vessel and returned to the conveyor in the step(2) through a further succeeding conveyor. After the melted sodium isflown down from the spent NaS cells in oil of the heating oil vessel,the workpiece-setting vessel into which the spent NaS cells are insertedis moved to a location for pulling out the inner tubes from the cells,and the inner tubes are pulled out from the cells there [See FIG. 1(7)].The workpiece-setting vessel in which the spent NaS cells having theinner tubes pulled out are placed is moved onto a succeeding conveyor[FIG. 1(8)], and then returned, by a further conveyor, to a position inthe step (3) for using it again [See FIG. 1(9)]. In FIGS. 1(2), (4) and(9), the pressing vessel member and/or the workpiece-setting vessel ismoved up and down by using an up-and-down means.

In an embodiment illustrated in FIG. 2, the pressing vessel member andthe workpiece-setting vessel are vertically inverted together with theNaS cells by using an appropriate inverter in step (4) so that the cutopenings of the cells may be directed downwardly in theworkpiece-setting vessel in the state the cut opening and faced with thetube pull-out holes of the workpiece-setting vessel. Consequently, oilflows from the cells through the cut openings and the inner tubepull-out holes. FIG. 2 shows a process and an apparatus substantiallyidentical with those in FIG. 1 except that the pressing vessel member isreturned to the position at (2) through (5), and the workpiece-settingvessel and the spent NaS cells are immersed into the oil inside theheating oil vessel by using a transporting elevator not shown [the step(6) of FIG. 2]. In FIG. 2, a part of the steps (8) and (9) of FIG. 1 isomitted.

In an embodiment of FIG. 3, spent NaS cells having cut openings are onceinserted into an appropriate vessel in step (2), and whether cut piecesare present at the cut openings or not is checked there. After any suchcut pieces are removed if necessary, the cells are held in theworkpiece-setting vessel having inner tube pull-out holes and placed ona conveyor in step (3) in the state that the cut openings are directeddownwardly and face-to-face with the inner tube pull-out holes of theworkpiece-setting vessel. Thereby, the oil in the cells flows out. Then,the workpiece-setting vessel into which the cells are inserted is movedonto a succeeding conveyor so as to move the workpiece-setting vessel ata location for transporting the cells into the heating oil vessel. Instep (5), the workpiece-setting vessel and the spent NaS cells areimmersed into oil in the heating oil vessel by using a transportingelevator not shown. With respect to the other features, FIG. 3 shows aprocess and an apparatus substantially identical with those in FIG. 1.Since no inversion step as in FIGS. 1 and 2 is necessary in theembodiment of FIG. 3, the process and the apparatus can be furthersimplified.

According to the present invention, the oil placed on the sodium insidethe inner tube and the oil inside the opening-cutting oil vessel may beidentical with oil such as flowing paraffin filled in the heating oilvessel. Alternatively, a different oil may be used for the former solong as it does not cause any trouble with the oil in the heating oilvessel.

FIG. 4 schematically shows an opener which may be used in the presentinvention for cutting an opening in the spent NaS cell for pulling outthe inner tube from the cell. In FIG. 4, oil 2 such as flowing paraffinis filled in an opening-cutting oil vessel 1. The spent NaS cell havingthe inner tube pull-out opening formed in the cathode cap is grasped bya chuck 4 at an upper outer peripheral end portion thereof, and theentire cell 3 grasped by the chuck 4 is immersed into the oil 2 by meansof an elevator not shown. The lower outer peripheral end portion of thespent NaS cell 3 immersed is held by a holder 5 provided at a bottomportion of the oil vessel 1. A cutter 6, such as hole saw, freely movingup and down, is arranged coaxially with the axis of the spent NaS cellheld vertically in the oil. After the axis of the cutter is aligned withthat of the cell 3, the cutter 6 is descended so that an opening havingan inner diameter substantially equal to or larger than that of theinner tube is formed by cutting. Since the entire cell is immersed inthe oil 2, oil is poured onto sodium inside the inner tube of the cell.For simplification of explanation, the first opening and the secondopening are totally referred to as "(cut) opening" hereinunder.Thereafter, the the cutter 6 is raised, and the chuck 4 with the cell 3is then raised. After excess oil is removed, the cell 3 is movedsidewise together with the chuck 4, and inserted into the pressingvessel member, the workpiece-setting vessel or the cut piece-checkingvessel shown in (2) in FIGS. 1 to 3. The cell having the opening formedis pulled up from the oil 2 in the oil vessel 1, and inserted into thepressing vessel member, the workpiece-setting vessel or the cutpiece-checking vessel by using an appropriate means instead of the chuck4.

In the following, the spent NaS cell disposal apparatus to be used inthe invention process for disposing of such spent cells will beexplained in more detail with reference to an embodiment illustrated inFIGS. 5 to 10.

FIG. 5(a) shows a shallow tray-shaped workpiece-setting vessel 7 and adeep tray-shaped pressing vessel member 8. Inside the workpiece-settingvessel 7 and the pressing vessel member 8 are provided partitions 7-1, .. . , 7-(n-1), and partitions 8-1, . . . , 8-(n-1), respectively, forreceiving "n" of the spent NaS cells. A hole 9 for pulling out the innertube from the spent NaS cell is provided in a bottom portion of each ofpartitioned chambers defined by the partitions in the workpiece-settingvessel 7. Since the spent NaS cell has a complicated multi-tubularstructure, only an outer tube 3a and an inner tube 3b are shown in FIG.5(a) in a simplified manner. The diameter of the inner tube pull-outhole 9 is set greater than the outer diameter of the inner tube 3b ofthe spent NaS cell but smaller than the inner diameter of the outer tube3a, so that the inner tube may be pulled out from the cell through thehole 9. The number "n" of the spent NaS cells can be simultaneouslyhandled by using the the workpiece-setting vessel 7 and the pressingvessel member 8 thus constructed. A flange 10 is provided at an open endof the workpiece-setting vessel 7, and a flange 11 is provided at anopen end of the pressing vessel member 8. After the spent NaS cells areplaced between the workpiece-setting vessel 7 and the pressing vesselmember 8, the spent NaS cells are vertically and laterally fixedly heldinside between the workpiece-setting vessel member 7 and the pressingvessel member 8 by fixedly butting the flange 10 of theworkpiece-setting vessel 7 and the flange 11 of the pressing vesselmember 8 [See FIG. 5(b)]. The pressing vessel member 8 functions toreceive the cells 3, and prevent the cells from falling when the upperfaces of the cells 3 are covered with the workpiece-setting vessel 7 andthe entire assembly is vertically inverted. So long as this function issatisfied, its structure is fundamentally arbitrary. The outer diameterof the flange 11 is made greater than that of the flange 10, so thatonly the pressing vessel member 8 can be pulled up through engagementbetween the flange 11 of the pressing vessel member and chuck pawl asexplained in connection with FIG. 10.

In the process and the apparatus shown in FIGS. 1 and 2, the workpiecesetting vessel 7 and the pressing vessel member 8 are used. In theprocess and the apparatus shown in FIG. 3, only the workpiece-settingvessel 7 is used.

FIG. 6 shows in detail the embodiment shown in FIG. 1, more specificallythe inverting step (1) [corresponding to (4) in FIG. 1], theimmersion/sodium flow-out step (2) [corresponding to (6) in FIG. 1], theinner tube pull-out step (3) [corresponding to (7) in FIG. 1], and thetake-out step (4) [corresponding to (8) in FIG. 1]. FIG. 6(1) shows aninverted state in which the upper workpiece-setting vessel 7 and thelower pressing vessel member 8, which are chucked together at theflanges 10, 11 to fixedly held the cells between them in the state thatthe openings of the spent NaS cells are directed upwardly, arevertically reversed.

FIG. 7 shows a state in which the upper workpiece-setting vessel 7 andthe lower pressing vessel member 8 are chucked together at the flanges10, 11 by means of the holding head 12 to fixedly hold the spent NaScells, in the state that the cut openings of the cells are directedupwardly. As shown in FIG. 7, the holding head 12 has a gate-shapedframe 13 defining such a space as to receive the workpiece-settingvessel 7 and the pressing vessel member 8 butted and chucked togetherand to vertically invert them. Rotary shafts 14a, 14b are journaled atlower ends of opposite legs of the frame 13, respectively. The rotaryshaft 14a located on the right side of FIG. 7 is a driving shaftprovided with a gear 15, and the other rotary shaft 14b located on theleft side is a follower shaft. The gear 15 meshes with a sector gear 17driven by a cylinder 16, and is rotated by the sector gear 17. The rightrotary shaft 14a is thereby rotated at least by 180°, so that theworkpiece-setting vessel 7 and/or the pressing vessel member 8 arevertically inverted.

L-shaped chuck pawls 18a, 18b are provided at tips of the rotary shafts14a, 14b, respectively, and movable chuck pawls 20a, 20b, which areturnable around shafts 19a, 19b, respectively, are opposed to the chuckpawls, respectively. The flange 10 of the workpiece-setting vessel 7 andthe flange 11 of the pressing vessel member 8 are chucked togetherbetween the chuck pawls 18a, 20a and between the chuck pawls 18b, 20b,respectively, by turning the chuck pawls 20a, 20b. As shown in FIG. 7,the movable chuck pawls 20a, 20b are connected to tips of push rods 21a,21b in the form of a cross slider crank so that the push rods 21a, 21bmay be inwardly or outwardly pushed to turn the chuck pawls 20a, 20b.When the push rods 21a, 21b are inwardly pushed, the chuck pawls 20a,20b are turned to press chucking faces 20a-1 and 20b-1 against theflange 10 of the workpiece-setting vessel 7 so that the movable chucks20a, 20b may be downwardly pressed to press the flange 11 of thepressing vessel member 8 against the flange 10 of the workpiece-settingvessel 7.

Small-size cylinders 22a, 22b are provided in the legs of thegate-shaped frame 13, and turnable levers 23a, 23b are connected to tipsof rods of the cylinders 22a, 22b at one upper end, and to engage withdouble jaw pin units 24a, 24b at the outer end portions of the push rodsat the the other lower ends, respectively. Thereby, the levers 23a, 23bare swingable around their respective supports at the center portionsthereof. Therefore, when the upper ends of the levers 23a, 23b areoutwardly pushed by the cylinders 22a, 22b, the lower end portions ofthe levers 23a, 23b inwardly push the push rods 21a, 21b, respectively.To the contrary, when the rods are retracted into the cylinders 22a,22b, respectively, the upper ends of the levers 23a, 23b are inwardlymoved to displace the push rods 21a, 21b outwardly. In this case, themovable chuck pawls are turned as shown in FIG. 10. The sector gear 17is provided with a large through-hole 17a as shown in FIG. 10, whichallows the lever 23a to be turned irrespective of the rotation of thesector gear.

In FIG. 7, the sector gear 17 is turned by the cylinder 16 to turn therotary shaft 14a via the gear 15 at 180°. At that time, the chuck pawl18a and the movable chuck pawl 20a are turned. On the other hand, therotary shaft 14b is correspondingly turned via the flanges 10, 11 of theworkpiece-setting vessel 7 and the pressing vessel member 8, the chuckpawl 18b and the movable chuck pawl 20b. Following this, theworkpiece-setting piece 7 and the pressing vessel member 8 between whichthe spent NaS cells 3 are set are vertically inverted to direct the cutopenings of the spent NaS cells downwardly (See FIGS. 6 and 9). Sincethe spent NaS cells are fixedly held between the workpiece-settingvessel 7 and the pressing vessel member 8, the cells do not fall duringthe above vertical inversion. The oil placed on the sodium inside theinner tubes of the spent NaS cells flows down through the downwardlydirected cut openings.

As shown in FIG. 6, a reciprocating beam 26 extends over the locationscorresponding to the steps (4) to (8) above the heating oil vessel 25filled with oil such as flowing paraffin, and the holding head 12 isadapted to be moved up and down relative to the reciprocating beam 26via a bearing 27 and a rod 28 slidably fitted into the bearing 27 and tobe moved along the reciprocating beam 26. The rod 28 is vertically movedby a cylinder 28 not shown. In FIG. 6, the holding head 12 is located ina right lower position in a zone where the the workpiece-setting vessel7 and the pressing vessel member 8 between which the spent NaS cells arefixedly held are set and chucked in the holding head 12. FIG. 6(1) andFIG. 9 show the vertically inverted state in which the workpiece-settingvessel 7 is located downwardly. In this state, the spent NaS cellsfixedly held between the workpiece-setting vessel 7 and the pressingvessel member 8 are immersed into the oil of the heating oil vessel 25,and the flange 10 of the workpiece-setting vessel 7 is placed on tworails 29 [See FIG. 6(2)]. Then, the push rods 21a, 21b are outwardlydisplaced to turn the chuck pawls 20a, 20b as shown in FIG. 10. Thereby,the chucked state of the flanges 10, 11 is released [See FIGS. 11(a) and11(b)]. In FIG. 6, when the rod 28 is pulled up by the cylinder, thefaces 20a-1, 20b-1 of the chuck pawls 20a, 20b butt the lower face ofthe flange 11 of the pressing vessel member 8 so that only the pressingvessel member 8 may be upwardly pulled up from the heating oil vessel25. Thereafter, the pressing vessel member 8 is returned to the positionin FIG. 6(1). The push rods 21a, 21b are inwardly pushed so that thechuck pawls 20a, 20b may be turned upwardly. Consequently, the faces20a-2, 20b-2 of the chuck pawls 20a, 20b are pressed against the lowerface of the flange 11 of the pressing vessel member 8, so that thepressing vessel member is chucked between the chuck pawls 18a, 20a andbetween 18b, 20b. Then, the pressing vessel member 8 is verticallyinverted. Next, the pressing vessel member 8 is removed from the holdinghead 12, and returned to the position (2) by means of the conveyor inFIG. 1(5) for using it again.

As shown in FIG. 6 by imaginary lines, it may be that the reciprocalbeam 26 itself is reciprocatingly movably fitted to a stationary beam sothat the immersing unit (27, 28), the pusher (30), and the take-out unit(32) may be interlockingly operated.

The spent NaS cells 3 left on the horizontal rails 29 are heated by theheating flowing paraffin, so that the sodium inside the cells is meltedand flows down into the bottom portion 25a of the heating oil vessel 25through the cut openings and the inner tube pull-out holes 9 of theworkpiece-setting vessel 7. At that time, since sodium does not almostcontact air, it is not oxidized. Therefore, sodium smoothly flows out.After the cells are left at this position for a given time to completelyremove the sodium, the workpiece-setting vessel 7 with the spent NaScells 3 is moved to the location for pulling out the inner tubes 3b ofthe cells along the horizontal rails 29 by means of a pusher 30 which ishanged from the reciprocating beam 26 and moved up and down andto-and-fro along the reciprocating beam 26. Then, the inner tubes 3b arepulled out from the cells by an inner tube 3b pull-out device 31 at theinner tube 3b pull-out position [FIG. 6(3)].

Although the inner tube 3b pull-out device 31 is not illustrated indetail, an appropriate chuck-out device may be used for this purpose.That is, expandable chucking pull-out pawls are inserted into the spentNaS cell 3 through the inner tube 3b pull-out hole 9 of theworkpiece-setting vessel 7 and the cut opening of the cell to chuck theinner tube 3b from the inner side. Then, the inner tube 3b is pulled outdownwardly, whereas the outer tube 3a of the spent NaS cell 3 is held bythe workpiece-setting vessel 7. The remaining, portions of the spent NaScells 3 in which the inner tube 3b are pulled out in this matter aretaken outside from the heating oil vessel 25 by means of a take-out head32 which is hanged from the reciprocating beam 26 and moved up and downand to-and-fro along the reciprocating beam 26 [FIGS. 6(3) and (4)].

The thus pulled out workpiece-setting vessel 7 with the remaining spentNaS cells is placed on the conveyor [FIG. 1(8)]. After the outercylinders of the spent NaS cells are removed from the workpiece-settingvessel 7 at the lifter table [FIG. 1(9)], the workpiece-setting vessel 7is carried to the location in FIG. 1(3) for using it again.

In the embodiment in FIG. 2, the assembly of the workpiece-settingvessel 7, the pressing vessel member 8, and the spent NaS cells fixedlyheld therebetween is vertically inversed at the location of (4). In thisembodiment, this assembly may be inversely inverted by a holding head,which is movable up and down relative to the reciprocating beam 26 butfixed in the longitudinal direction. In the embodiments in FIGS. 2 and3, the workpiece-setting vessel 7 which is positioned near and outsidethe heating oil vessel 25 and into which the spent NaS cells areinserted can be moved up and immersed into the oil in the heating oilvessel 25 by using a transporting elevator movable along thereciprocating beam 26 and having no reversing mechanism.

In FIG. 6, it may be that a wheel truck is run along the reciprocatingbeam 26, and the cylinder hangs from the wheel truck. Three wheel trucksmay be interlockingly operated.

What is claimed is:
 1. A process for disposing of a spent NaS cell, comprising the steps of:cutting the NaS cell to form at least one opening to expose an inner tube and sodium in the NaS cell; flowing oil into the NaS cell through the at least one opening while the NaS cell is positioned upright, to cover the sodium with the oil; inverting the NaS cell such that the at least one opening faces a downward direction, the NaS cell being supported by a workpiece setting vessel that provides access to permit removal of the inner tube through the at least one opening; immersing the NaS cell supported by the workpiece setting vessel in heated oil provided in a heating oil vessel while the NaS cell is inverted, whereby the sodium in the NaS cell is melted and flows out of the NaS cell; and removing the inner tube from the NaS cell through the at least one opening.
 2. The process of claim 1, wherein said at least one opening comprises a first opening formed in the NaS cell and a second opening formed in the inner tube, said first and second openings being formed by cutting.
 3. The process of claim 1, wherein said NaS cell is placed between the workpiece setting vessel and a pressing vessel member, said workpiece setting vessel has a hole in communication with said at least one opening formed in the NaS cell, and the workpiece setting vessel and the pressing vessel member having the NaS cell supported therein are inverted such that the opening is directed downwardly.
 4. The process of claim 2, wherein said NaS cell is placed between the workpiece setting vessel and a pressing vessel member, said workpiece setting vessel has a hole in communication with said first and second openings formed in the NaS cell, and the workpiece setting vessel and the pressing vessel member having the NaS cell supported therein are inverted such that the opening is directed downwardly.
 5. The process of claim 3, wherein the pressing vessel member is removed after inversion.
 6. The process of claim 4, wherein the pressing vessel member is removed after inversion.
 7. The process of claim 3, wherein the pressing vessel member, the workpiece setting vessel and the NaS cell are inverted immediately before immersion such that the oil inside the inner tube flows therefrom.
 8. The process of claim 4, wherein the pressing vessel member, the workpiece setting vessel and the NaS cell are inverted immediately before immersion such that the oil inside the inner tube flows therefrom.
 9. The process of claim 1, wherein the at least one opening is formed by cutting the NaS cell in an opening-cutting oil vessel containing the oil, such that the oil flow into the NaS cell. 